1. Field of the invention
The present invention relates to a printer control system for controlling the printing of an object on a support in a number of pass images on top of each other, the object having a surface of varying height, the printer control system comprising a user interface having a display device and arranged to visualize in a window on the display device a preview image before printing of the object, the preview image comprising a representation of the surface of the object.
The present invention also relates to a printing system for printing of an object on a support in a number of pass images on top of each other, the object having a surface of varying height, the printing system comprising a printer control system according to the invention.
The term “printing” or “print” refers to building an object from print material by additive manufacturing, and includes, in particular, jetting print material for depositing the print material on the support or an already printed portion of the object.
The term “printer control system” and “print controller” refer to the same.
2. Description of the Related Art
Print systems are known that allow printing of multilayer structures that can reach a considerable height as compared to conventionally printed images that are basically flat, or, at least, the height of which is generally disregarded. The structures are generated by stacking layers of material on top of each other. For example, radiation curable ink, in particular UV curable ink, may be used. By repeatedly printing a layer on top of a previously printed, cured layer, a multilayer structure may be built up having a defined height. For example, the height may be up to 10 mm or more. The height, i.e. the thickness of the printed structures, adds an extension in a further dimension to the two dimensional image, and, accordingly, such prints are termed 2.5D prints or relief prints. The printed structure may comprise an image, e.g. a color image.
U.S. Pat. No. 8,976,415 describes a method for generating relief prints, including processing a relief image, comprising color channels for indicating a color of each pixel and a height channel for indicating a height of each pixel, into several passes that are printed using a printer with several colorants including a white colorant. For each pixel a relief part, a white part and a skin part are discriminated. A height variation of individual pixels is caused by repetitive printing of colorants in the relief part. A number of pass images are derived from the relief image to be printed on top of each other. All available colorants may be used in the relief part, in order to provide for an optimal print speed for this part. The skin part comprises pass pixels for which a colorant composition based on the color channels of the relief image is established. Hereinafter the relief part is also mentioned as underground of the object to be printed. Hereinafter the skin part is also mentioned as surface of the object to be printed.
For printing relief prints or 3D prints, an object is built by stacking layers of material on top of each other. A slicing technique is known that consists in decomposing the object into a set of horizontal layers, which are printed on top of each other.
One of the well-known issues of 3D printing is a stair case or contouring effect due to a construction of a print model of the digital object to be printed slice by slice in the field of inkjet additive manufacturing. A problem is that contour lines may be observable only once the print is finished. Printing large size 2.5 D or 3D designs on an inkjet printing system is an expensive and time-consuming operation.
It is an objective of the present invention to provide a printing system facilitate fast printing of relief prints or 3D prints with high surface quality or, in general, enhanced visual print quality of a relief or 3D printed object.